Out of any video game you’ve ever played what is or was your favorite boss fight ever?

Assassins Creed Unity Arno vs Bellec. Fantastic set pieces, fun fight, and idk if it was a bug or not but it turned off the indicator for a counter or parry so you has to stay alert and time it right yourself. Fun fight and cinematic in the right ways.

And more recently Thor from God of War Rangarok.